No abstract

Natto was made in a laboratory scale from soybean using 2 steaming times, 9 Bacillus natto strains, and 6 fermentation times. Natto characteristics including color, firmness, viscosity, ammonia content, and bacteria population were determined. The highest viscosity value of the final products was the natto inoculated with B. natto "Itobiki strain"; the 2nd was natto with B. natto NRRL B-3383 strain. A higher steaming time reduced fermentation time and ammonia content in the final products. A combination of soaking at the room temperature for 20 h (weight increase ratio: 2.1 to 2.3), steaming at 121°C for 40 min, inoculated with "Itobiki strain" or NRRL-3383 strain, and fermented at 40 to 42°C for 18 h was able to produce good natto products in a laboratory scale.

The 2001 durum wheat crop grown in the Northern Plains was surveyed for microbial loads, mycotoxins, and quality. Correlations among these factors were identified. Effects of cleaning, milling, and pasta processing on microbial loads and deoxynivalenol (DON) concentrations were determined. Aerobic plate counts (APCs), mold and yeast counts (MYCs), internal mold infection (IMI), and internal Fusarium infection (IFI) were lowest in grain samples from Montana and highest in grain from northeastern North Dakota. DON and 15-acetyldeoxynivalenol (15-ADON) were not detected in samples from Montana. Nivalenol was not detected in any samples. DON in North Dakota samples ranged from none detected to 23 micrograms/g. 15-ADON was detected in a few North Dakota samples, with a maximum of 0.8 microgram/g. DON positively correlated with APCs, MYCs, IFI, damaged kernels, total defects, U.S. grade number, and tombstone kernel content and negatively correlated with test weight, vitreous kernel content, and kernel weight. APCs, MYCs, and DON concentrations were lower in semolina than whole grain. Processing semolina into spaghetti did not change DON concentrations. APCs for spaghetti were reduced 2.2 to 4.1 logs from those for semolina, whereas MYCs were reduced 0.1 to 1.7 log. Some APCs in durum flour and semolina were higher than certain industry specifications would allow, although other factors were acceptable. However, microbial loads in the spaghetti were all within specifications found in the available literature.

Ozonated water is reported to be effective in reducing the microbial load in foods such as fruits, vegetables, and grains. Ozonated water may be an effective alternative to chlorinated water in treating durum wheat before milling. Therefore, durum wheat was washed with ozonated water and analyzed for yeast and mold count (YMC) and aerobic plate count (APC). A system for producing and monitoring ozonated water was developed. The effect of water quality (tap, distilled, and ultra-pure), temperature (7, 15, and 25 degrees C), and pH (2, 4, and 6.5) was evaluated on the following: steady-state dissolved ozone concentration, ozone decay constant, half-life, mass transfer coefficient, equilibrium ozone concentration, and solubility ratio. The study of these parameters was important to attain a stable, high dissolved ozone concentration at the outset of washing and to have information for system improvement and scale-up. A 1% acetic acid solution (pH 2) at 15 degrees C resulted in high dissolved ozone concentration (21.8 mg/L) and long half-life (9.2 min). Subsequently, wheat was washed with 5 wash water types: distilled water, ozonated water (16.5 mg/L), chlorinated water (700 mg/L), acetic acid solution (1%), and acetic acid + ozonated water (1%, 20.5 mg/L). The treated samples were analyzed for YMC and APC. The acetic acid + ozonated water treatment was the most effective, with a reduction of 4.1 and 3.2 log(10) colony forming units/g in YMC and APC, respectively. Though ozonated water was not very effective alone, it was useful in combination with acetic acid.

The effects of high-temperature and -pressure processing of foods spiked with deoxynivalenol (DON) were examined. In extruded corn grits, extruded dry dog food, and autoclaved moist dog food, there were no significant reductions (P < 0.05) in DON after processing. Autoclaved cream-style corn showed a reduction in DON of only 12%. Overall, DON was stabile to the high temperature and pressure processes tested. The use of an alpha-amylase in the extraction method for analysis by an enzyme-linked immunosorbant assay (ELISA) improved the recovery of DON from the spiked extruded and autoclaved products by as much as 26% over the standard ELISA method.